It has been known in the art to provide an internal combustion engine with a turbocharger to boost air pressure and engine power. Such engines typically have a fuel system which injects or otherwise provides fuel to mix with the boosted air and provide a gas mixture to a combustion chamber(s) of the internal combustion engine. Combustion of the gas mixture in the combustion chamber(s), under pressure ignition, generally provides good combustion and a relatively clean exhaust gas mixture. However, with more stringent government regulations, additional measures are required to obtain even cleaner exhaust gas mixtures with reduced emissions of carbon dioxide, nitrous oxides, sulfur dioxide, particle and soot emissions are needed.
Attempts have been made to reduce the amount of undesirable compounds in the exhaust emissions of an internal combustion engine. One system commonly used returns a portion of the exhaust gas mixture emitted from the combustion chamber after combustion back to the combustion chamber to be mixed with the gas mixture to be combusted. Such a system is successful in reducing somewhat some oxides of nitrogen in the exhaust gas mixture. However, additional treatment of the exhaust gas under more stringent regulations may be required.
Exhaust gas catalytic converters have been used in the exhaust system for many years. Such converters have been satisfactory in removing a greater amount of oxides of nitrogen. However, catalytic converters do not satisfactorily remove sulfur dioxide when fuel having a high sulfur content is used. As a result, the cost of operation of the internal combustion engine increases when low sulfur fuels are required. Finally, the exhaust gas catalytic converter consumes energy and reaction substances, for example, urea resulting in high operational costs.
In ship applications, strict restrictions apply in most regions of the world with respect to soot and particle emissions of the internal combustion engine. Steps in reducing emissions of nitrous oxides can lead to an increase in soot emissions of the internal combustion engine. Also, certain ship maneuvering operations can lead to a deterioration in combustion conditions in the combustion chamber of the internal combustion engine (a too rich air/fuel ratio). No satisfactory solution to this problem has been made.
Exhaust gas turbine driven electrical generators are occasionally used to exploit mechanical residual working capacity of the exhaust gas mixture. The exhaust gas turbine driven generator is separate from and in addition to the exhaust gas turbine of the turbocharger and receives the exhaust gas mixture after the exhaust gas turbine the turbocharger. A separate exhaust gas turbine driven electrical generator, such as this, has a low efficiency because of the low useable pressure drop of the exhaust gas mixture and adds additional cost and complexity.
Separate steam turbine electrical generator assemblies are commonly used in combination with diesel engines to produce electrical energy. In such arrangements a condenser is required to dissipate heat, unused, into seawater or a cooling tower. The effectiveness of this combination is low however because of a high cost and an undesirable loss of condensation.
State of the art internal combustion engines have a high rate of turbocharging resulting in a reduced transient response capability. As a result, the turbocharger is not able to deliver sufficient energy in a relatively short period of time.
The present invention is directed at overcoming one or more of the problems set forth above.